Publications by authors named "Pavel A Stuzhin"

Axial modification of boron (III) subphthalocyanine bromides with 4-hydroxy-benzoic acid successfully led to the formation of the macrocycles with anchored 4-carboxyphenoxy group [RsPcPHBA] (R=Bu, H) in the axial position and to a new dimer [sPcPHBAsPc] as minor product. Tri-tert-butyl and unsubstituted subphthalocyanines bearing benzoate ([BusPcBA], [sPcBA]), phenoxy-group ([BusPcOPh], [sPcOPh])) in the axial position, have been also investigated as well as control sPcs. All compounds were characterized by NMR, IR, UV-Vis and mass spectrometry.

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The luminescent and photophysical properties of the etioporphyrin-I complex with indium(III) chloride, InCl-EtioP-I were experimentally studied at room and liquid nitrogen temperatures in pure and mixed toluene solutions. At 77 K, in a 1:2 mixture of toluene with diethyl ether, the quantum yield of phosphorescence reaches 10.2%, while the duration of phosphorescence is 17 ms.

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Spectral luminescence, kinetic and energetic properties of hexachlorosubphthalocyaninatoboron(III) chloride and its azaanalogue containing fused pyrazine fragments instead of benzene rings were studied at 298 and 77 K. Weak phosphorescence of complexes was detected and characterized in near-infrared region of spectrum, its parameters depend substantially on the presence of methyl iodide due to its external effect of heavy atom in solutions. Quantum yields of photosensitized formation of singlet oxygen were determined by the relative luminescence method.

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The template cyclomerization of the iminoimide derivatives (obtained by the treatment of diarylfumarodinitriles with NH in methanol containing catalytic amounts of dissolved Na) in the presence of SiCl in pyridine leads to silicon(IV) octaarylporphyrazine complexes ((HO)SiPzAr, Ar = Ph, BuPh) as a main reaction product. In the case of phenyl-substituted derivative, the formation of a distinctive Si(IV) complex as a byproduct was observed, which according to mass-spectroscopy measurement contains the macrocycle with five diphenylpyrrolic units. The treatment of bishydroxy complexes with tripropylchlorosilane in the presence of magnesium in pyridine leads to the formation of axially siloxylated porphyrazines (PrSiO)SiPzAr, followed by the reductive contraction of the macrocycle and formation of the corresponding corrolazine complexes (PrSiO)SiCzAr.

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A new complex of indium(III)chloride with etioporphyrin-I was synthesized and characterized. As with naturally occurring extraligated etioporphyrins, the InCl-EtioP-I spectrum in solution has a very strong B-band and a more than an order of magnitude weaker Q-band, but this difference diminishes in solid films of InCl-EtioP-I obtained by thermal evaporation in vacuum. In a solid, molecules have a tight convex-convex arrangement in a 2D double layered structure with interplane distance of 3.

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A series of 5,7-disubstituted 1,4-diazepinoporphyrazinato magnesium(II) and nickel(II) complexes, including two novel compounds, were obtained by metal-templated macrocyclization. A combination of X-ray diffraction, H NMR, UV-vis, and electrochemical analyses allowed us to study their tendency towards H-type dimerization and trace the influence of structural and solvation factors on dimer stability. Based on the physicochemical and theoretical DFT calculation data, it was found that the main binding forces between 6-1,4-diazepinoporphyrazine decks in the dimers were efficient π-π donor-acceptor interactions induced by the interdeck C-H⋯N hydrogen bonds.

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Electronic and geometric structures of metal-free, Al, Ga and In complexes with tetrapyrazinoporphyrazine (TPyzPA) and octachlorotetrapyrazinoporphyrazine (TPyzPACl) were investigated by density functional theory (DFT) calculations and compared in order to study the effect of chlorination on the structure and properties of these macrocycles. The nature of the bonds between metal atoms and nitrogen atoms was described using the NBO-analysis. Simulation and interpretation of electronic spectra were performed with the use of time-dependent density functional theory (TDDFT).

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Phosphorus(V) complexes of octaphenyltetrapyrazinocorrolazine bearing two aryloxy groups in the axial position, [P(OAr)] (2a-c, Ar = phenyl (2a), 4-dimethylaminophenyl (2b), and 4-hydroxyphenyl (2c)), were prepared using a one-pot procedure by consecutive treatment of the dihydroxidophosphorus(V) derivative, [P(OH)] (1), with SOCl and then with the corresponding phenol ArOH. Complex 2a containing axial PhO groups is fluorescent in all studied solvents (toluene, CHCl, THF, and DMSO, ∼ 0.16-0.

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The basic macrocyclic octapyridinotetrapyrazinoporphyrazine In complex of formula [PyTPyzPzIn(OAc)]·8HO, prepared by reaction of the free ligand [PyTPyzPzH]·2HO with In(OAc), is a stable-to-air species of which the structure has been studied by its X-ray powder diffraction and mass spectra and characterization operated by IR and UV-visible spectral behavior. The complex has been further examined and proven to be of potential interest for its response as an anticancer agent in the field of photodynamic therapy (PDT), the value of Φ = 0.55 (in DMF) being in the range of 0.

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The electronic and molecular structures of metal-free tetrabenzoporphyrin () and its complexes with zinc, cadmium, aluminum, gallium and indium were investigated by density functional theory (DFT) calculations with a def2-TZVP basis set. A geometrical structure of and was found to possess D symmetry; , and were non-planar complexes with C symmetry. The molecular structure of belonged to the point symmetry group of D.

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Novel water-soluble dihydroxophosphorus(V) complexes of sulphophenyl substituted porphyrazine (6), corrolazine (7) and its pyrazine fused derivative (8) were prepared and their spectral, acid-base and photophysical properties in aqueous solutions were studied. Due to the presence of eight SOH groups, the compounds were fully monomeric (7 and 8) or only slightly aggregated (6) in water. Spectrophotometric titration revealed that the two stage deprotonation of axially bonded hydroxy groups can be achieved for porphyrazine 6 (p = 5.

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The Knudsen effusion method with mass spectrometric control of the vapor composition was used to study the possibility of a congruent transition to the gas phase and to estimate the enthalpy of sublimation of metal-free tetrakis(1,2,5-thiadiazolo)porphyrazine and its nickel complex (HTTDPz and NiTTDPz, respectively). The geometrical and electronic structure of HTTDPz and NiTTDPz in ground and low-lying excited electronic states were determined by DFT calculations. The electronic structure of NiTTDPz was studied by the complete active space (CASSCF) method, following accounting dynamic correlation by multiconfigurational quasi-degenerate second-order perturbation theory (MCQDPT2).

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Reaction of (2,3,9,10,16,17,23,24-octabutylphthalocyaninato)lanthanide(iii) acetylacetonates (BuPcLn(acac), 1a-c, Ln = Lu (a), Eu (b), La (c)) with a tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazine ligand (tBuPhDzPzH2, 2) produced sandwich compounds (tBuPhDzPz)Ln(BuPc) (3a-c), which represent the first heteroleptic double-deckers incorporating both Pc and DzPz decks. A combination of high-resolution mass spectrometry, UV-Vis/NIR, MCD, and 1H NMR spectroscopy, and square-wave voltammetry provided unambiguous characterization of target complexes 3 indicating that their spectral and electrochemical properties are generally intermediate with respect to their homoleptic relatives. Based on the data of solution-state 1H-1H NMR (COSY, NOESY) correlation spectroscopy supported by DFT calculations, a dimerization tendency of compounds 3 proportional to the Ln(iii) ion size was found.

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Electronic and geometric structures of Y, La and Lu complexes with porphyrazine (Pz) and tetrakis(1,2,5-thiadiazole)porphyrazine (TTDPz) were investigated by density functional theory (DFT) calculations and compared. The nature of the bonds between metal atoms and nitrogen atoms has been described using the analysis of the electron density distribution in the frame of Bader's quantum theory of atoms in molecule (QTAIM). Simulation and interpretation of electronic spectra were performed with use of time-dependent density functional theory (TDDFT) calculations.

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Although subphthalocyanines (SubPcs) possess advantageous fluorescence properties and serve as an amazing tool to attach a recognition sensor moiety to the axial position, a limited number of switchable SubPcs have been described so far. Isosteric aza-replacement is known to improve sensing properties in closely related phthalocyanine families; however, pyrazino[2,3-b,g,l]subporphyrazines (SubPyzPzs) have not yet been investigated for use in sensing applications. Therefore, this project focuses on the synthesis and sensing abilities of pH-sensitive SubPcs and SubPyzPzs on the principle of photoinduced electron transfer (PET).

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Electronic and geometric structures of Ca(II) and Zn(II) complexes with porphyrazine (Pz) and tetrakis(1,2,5-thiadiazole)porphyrazine (TTDPz) were investigated by density functional theory (DFT) calculations and compared. The perimeter of the coordination cavity was found to be practically independent on the nature of a metal and a ligand. According to the results of the natural bond orbital (NBO) analysis and quantum theory of atoms in molecules (QTAIM) calculations, Ca-N bonds possess larger ionic contributions as compared to Zn-N.

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The autocyclotetramerization of the precursor 2,3-dicyano-5,6-di(2'-pyridyl)pyrazine [(CN)PyPyz] in the presence of MCl compounds (M = Al, Ga) leads to the formation of the new mononuclear porphyrazine complexes [PyTPyzPzMCl]·HO (PyTPyzPz = tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazinato anion). From these species, the hydroxide analogues [PyTPyzPzMOH]·HO were obtained by contact with hot water, and their corresponding pentanuclear species [(PdCl)PyTPyzPzMCl]·HO could be easily formed by the reaction with PdCl. Physicochemical characterization of the mono- and pentanuclear macrocycles was based on elemental analysis, and mass, powder X-ray, and IR spectra.

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The template cyclotetramerization of 1,2,5-thiadiazolo-3,4-dicarbonitrile in the presence of lithium n-butoxide in n-butanol leads to the Li(i) complex of tetrakis(1,2,5-thiadiazolo)porphyrazine. Various possible structures of dilithium and monolithium complexes have been considered by DFT/B3LYP molecular modelling using the cc-pvtz basis set, and their theoretical IR and UV-VIS spectra have been calculated. The experimental Li NMR, IR and UV-VIS spectra measurements show that the complex contains two inequivalent lithium atoms - one is coordinated to the macrocyclic dianion to form the anionic lithate complex [TTDPaLi], while the other forms the solvated countercation [Li(Solv)].

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5,7-Substituted 1,4-diazepinoporphyrazine magnesium(ii) complexes were synthesized via Mg(ii)-alkoxide templated macrocyclization. A single crystal growth synchrotron diffraction analysis permitted what is to our knowledge the first structural characterization of a 1,4-diazepinoporphyrazine. It exists as a dimer in the solid state.

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The first tellurium-containing phthalocyanine analogues have been prepared and spectroscopically characterised: the Mg(II) complex of tetra(1,2,5-telluradiazolo)porphyrazine and a low-symmetry tert-butyl substituted Mg(II) tribenzoporphyrazine with one fused 1,2,5-telluradiazole ring. It was observed that the introduction of Te atom(s) reduces the energy of the Q-transition, facilitates the reduction of the macrocycle and strongly increases the conductivity of thin films.

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Monoribbed-substituted mono- and dicyano-functionalized iron(II) macrobicycles were obtained for the first time by the reaction of iron(II) diiodoclathrochelate precursor with copper(I) cyanide-triphenylphosphine complex under mild conditions. The target dinitrile clathrochelate is a minor product of this reaction, whereas the major product contains only one cyano group. The clathrochelates obtained were characterized using elemental analysis, (1)H and (13)C{(1)H} NMR, IR and UV-vis spectroscopy, MALDI-TOF spectrometry and X-ray diffraction crystallography.

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The chloroiron(III) complex of 2,8,12,18-tetrabutyl-3,7,13,17-tetramethyl-5,10-diazaporphyrin, [(Cl)FeMBDAP], was prepared and studied by X-ray crystallography and by solution (1)H NMR and UV-vis measurements. In the crystal structure of hemisolvate [(Cl)FeMBDAP] x 0.5CHCl(3), two nonequivalent [(Cl)FeMBDAP] units containing Fe1 and Fe2 are arranged in pi-dimers with considerable overlap on their concave sides.

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The redox properties of the phthalocyanine-like tetrakis(thiadiazole)porphyrazines, [TTDPzM] (M = MgII(H2O), ZnII, CuII, 2HI), were investigated by cyclic voltammetry, and their ground- and excited-state electronic properties were studied in detail by density functional theory (DFT) and time-dependent DFT (TDDFT) methods. Bulk and specific (axial ligation) solvent effects on the molecular and electronic structure were also taken into account. The title compounds show stepwise reversible ligand-centered one-electron reductions in the range 0 to -2.

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Monometallic derivatives of tetrakis(1,2,5-thiadiazole)porphyrazine, [TTDPzH2], with main group tervalent metal ions having the formulae [TTDPzMX] (TTDPz = tetrakis(1,2,5-thiadiazole)porphyrazinato dianion; M = Al(III), X = Cl-, Br-, OH-; M = Ga(III), X = Cl-, OH-; M = In(III), X = AcO-) were prepared and investigated by single-crystal X-ray analysis and IR and UV-vis spectroscopy as well as cyclic voltammetry and spectroelectrochemistry. The complexes [TTDPzMX] (M = Al(III), X = Cl-, Br-; M = Ga(III), X = Cl-) were obtained by direct autocyclotetramerization of the precursor 3,4-dicyano-1,2,5-thiadiazole in hot quinoline in the presence of MX3 salts (M = Al(III), Ga(III); X = Cl-, Br-) and were hydrolized to form the corresponding hydroxide derivatives, [TTDPzMOH]. The In(III) complex, [TTDPzIn(OAc)], was obtained from the free-base macrocycle [TTDPzH2] with In(OH)(OAc)2 in CH3COOH.

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